1. Field of the Invention
This invention relates to an optical disc apparatus and method for controlling turntable rotation, and more particularly to an optical disc apparatus having a turntable arranged to mount thereon an optical disc, such as CD-ROM, CD-RW, DVD and so on, and having a vibration suppressing function, such as with a balancer, and a method for controlling turntable rotation.
2. Prior Art
The present applicant has disclosed, in Japanese Utility Model Registration Application No. H9-6240, one example of a turntable having a vibration suppressing function. This turntable has a balancer accommodated within an annular space formed coaxially to a rotation center of its main body. During reproduction with a disc, the balancer automatically comes to rest at a predetermined position in response to an eccentricity of the turntable gravity center, thereby keeping the turntable in balanced rotation and hence suppressing against vibrations.
In the above-mentioned turntable, the optimal position of the balancer is different depending upon rotation speed of the turntable. On the other hand, the balancer once brought into rest will not readily move even if the turntable rotation speed is varied. Accordingly, where the rotation speed of the turntable is increased from a speed of 4 times the normal speed up to a speed of 32 times the normal speed, the turntable rotates at the 32-times speed in spite that the balancer remains resting at an optimal position for the 4-times speed. Due to this, there has been a difficulty in suppressing vibrations to a sufficient extent when the turntable is rotated at the 32-times speed.